Known as de "Godfader of Broadband",[12] de "Fader of Fiber Optics",[13][14][15][16][11] and de "Fader of Fiber Optic Communications",[17][18] Kao was awarded de 2009 Nobew Prize in Physics for "groundbreaking achievements concerning de transmission of wight in fibers for opticaw communication".[19]

A bundwe of siwica gwass fibres for opticaw communication, which are de de facto worwdwide standard. Kao awso first pubwicwy suggested dat siwica gwass of high purity is an ideaw materiaw for wong range opticaw communication, uh-hah-hah-hah.[40]

In de 1960s at Standard Tewecommunication Laboratories (STL) based in Harwow, Essex, Kao and his co-workers did deir pioneering work in de reawisation of fibre optics as a tewecommunications medium, by demonstrating dat de high-woss of existing fibre optics arose from impurities in de gwass, rader dan from an underwying probwem wif de technowogy itsewf.[41]

In 1963, when Kao first joined de opticaw communications research team he made notes summarising de background[42] situation and avaiwabwe technowogy at de time, and identifying de key individuaws[42] invowved. Initiawwy Kao worked in de team of Antoni E. Karbowiak (Toni Karbowiak), who was working under Awec Reeves to study opticaw waveguides for communications. Kao's task was to investigate fibre attenuation, for which he cowwected sampwes from different fibre manufacturers and awso investigated de properties of buwk gwasses carefuwwy. Kao's study primariwy convinced himsewf dat de impurities in materiaw caused de high wight wosses of dose fibres.[43] Later dat year, Kao was appointed head of de ewectro-optics research group at STL.[44] He took over de opticaw communication program of STL in December 1964, because his supervisor, Karbowiak, weft to take de Chair in Communications in de Schoow of Ewectricaw Engineering at de University of New Souf Wawes (UNSW), Sydney, Austrawia.[45]

Awdough Kao succeeded Karbowiak as manager of opticaw communications research, he immediatewy decided to abandon Karbowiak's pwan (din-fiwm waveguide) and overaww change research direction wif his cowweague George Hockham.[43][45] They not onwy considered opticaw physics but awso de materiaw properties. The resuwts were first presented by Kao to de IEE in January 1966 in London, and furder pubwished in Juwy wif George Hockham (1964–1965 worked wif Kao).[46]a[›] This study first deorized and proposed to use gwass fibres to impwement opticaw communication, de ideas (especiawwy structuraw features and materiaws) described are wargewy de basis of today's opticaw fibre communications.[citation needed]

In 1965,[44][47]b[›] Kao wif Hockham concwuded dat de fundamentaw wimitation for gwass wight attenuation is bewow 20 dB/km (decibews per kiwometer, is a measure of de attenuation of a signaw over a distance), which is a key dreshowd vawue for opticaw communications.[48] However, at de time of dis determination, opticaw fibres commonwy exhibited wight woss as high as 1,000 dB/km and even more. This concwusion opened de intense race to find wow-woss materiaws and suitabwe fibres for reaching such criteria.[citation needed]

Kao, togeder wif his new team (members incwuding T. W. Davies, M. W. Jones, and C. R. Wright), pursued dis goaw by testing various materiaws. They precisewy measured de attenuation of wight wif different wavewengds in gwasses and oder materiaws. During dis period, Kao pointed out dat de high purity of fused siwica (SiO2) made it an ideaw candidate for opticaw communication, uh-hah-hah-hah. Kao awso stated dat de impurity of gwass materiaw is de main cause for de dramatic decay of wight transmission inside gwass fibre, rader dan fundamentaw physicaw effects such as scattering as many physicists dought at dat time, and such impurity couwd be removed. This wed to a worwdwide study and production of high-purity gwass fibres.[49] When Kao first proposed dat such gwass fibre couwd be used for wong-distance information transfer and couwd repwace copper wires which were used for tewecommunication during dat era, his ideas were widewy disbewieved; water peopwe reawized dat Kao's ideas revowutionized de whowe communication technowogy and industry.[50]

He awso pwayed a weading rowe in de earwy stage of engineering and commerciaw reawization of opticaw communication, uh-hah-hah-hah.[51] In spring 1966, Kao travewed to de U.S. but faiwed to interest Beww Labs, which was a competitor of STL in communication technowogy at dat time.[52] He subseqwentwy travewed to Japan and gained support.[52] Kao visited many gwass and powymer factories, discussed wif various peopwe incwuding engineers, scientists, businessmen about de techniqwes and improvement of gwass fiber manufacture. In 1969, Kao wif M. W. Jones measured de intrinsic woss of buwk-fused siwica at 4 dB/km, which is de first evidence of uwtra-transparent gwass. Beww Labs started considering fibre optics seriouswy.[52]

Kao devewoped important techniqwes and configurations for gwass fibre waveguides, and contributed to de devewopment of different fibre types and system devices which met bof civiw and miwitaryc[›] appwication reqwirements, and peripheraw supporting systems for opticaw fiber communication, uh-hah-hah-hah.[51] In mid-1970s, he did seminaw work on gwass fiber fatigue strengf.[51] When named de first ITT Executive Scientist, Kao waunched de "Terabit Technowogy" program in addressing de high freqwency wimits of signaw processing, so Kao is awso known as de "Fader of de Terabit Technowogy Concept".[51][53] Kao has pubwished more dan 100 papers and was granted over 30 patents,[51] incwuding de water-resistant high-strengf fibers (wif M. S. Makwad).[54]

At an earwy stage of devewoping optic fibres, Kao awready strongwy preferred singwe mode for wong-distance opticaw communication, instead of using muwti-mode systems. His vision water was fowwowed and now is appwied awmost excwusivewy.[49][55] Kao was awso a visionary of modern submarine communications cabwes and wargewy promoted dis idea. He predicted in 1983 dat worwd's seas wouwd be wittered wif fibre optics, five years ahead of de time dat such a trans-oceanic fibre-optic cabwe first became serviceabwe.[56]

Awi Javan's introduction of a steady hewium–neon waser and Kao's discovery of fibre wight-woss properties now are recognized as de two essentiaw miwestones for de devewopment of fiber-optic communications.[45]

Kao joined de Chinese University of Hong Kong (CUHK) in 1970 to found de Department of Ewectronics, which water became de Department of Ewectronic Engineering. During dis period, Kao was de reader and den de chair Professor of Ewectronics at CUHK; he buiwt up bof undergraduate and graduate study programmes of ewectronics and oversaw de graduation of his first students. Under his weadership, de Schoow of Education and oder new research institutes were estabwished. He returned to ITT Corporation in 1974 (de parent corporation of STC at dat time) in de United States and worked in Roanoke, Virginia, first as Chief Scientist and water as Director of Engineering. In 1982, he became de first ITT Executive Scientist and was stationed mainwy at de Advanced Technowogy Center in Connecticut.[16] Whiwe dere, he served as an adjunct professor and Fewwow of Trumbuww Cowwege at Yawe University. In 1985, Kao spent one year in West Germany, at de SEL Research Centre. In 1986, Kao was de Corporate Director of Research at ITT.

Kao was de vice-chancewwor of de Chinese University of Hong Kong from 1987 to 1996.[58] From 1991, Kao was an Independent Non-Executive Director and a member of de Audit Committee of de Varitronix Internationaw Limited in Hong Kong.[59][60] From 1993 to 1994, he was de President of de Association of Soudeast Asian Institutions of Higher Learning (ASAIHL).[61] In 1996, Kao donated to Yawe University, and de Charwes Kao Fund Research Grants was estabwished to support Yawe's studies, research and creative projects in Asia.[62] The fund currentwy is managed by Yawe University Counciws on East Asian and Soudeast Asian Studies.[63] After his retirement from CUHK in 1996, Kao spent his six-monf sabbaticaw weave at de Imperiaw Cowwege London Department of Ewectricaw and Ewectronic Engineering; from 1997 to 2002, he awso served as visiting professor in de same department.[64]

Kao was chairman and member of de Energy Advisory Committee (EAC) of Hong Kong for two years, and retired from de position on Juwy 15, 2000.[65][66] Kao was a Member of de Counciw of Advisors on Innovation and Technowogy of Hong Kong, appointed on Apriw 20, 2000.[67] In 2000, Kao co-founded de Independent Schoows Foundation Academy, which is wocated in Cyberport, Hong Kong.[68] He was its founding Chairman in 2000, and stepped down from de Board of de ISF in December 2008.[68] Kao was de keynote speaker at IEEEGLOBECOM 2002 in Taipei, Taiwan, uh-hah-hah-hah.[69] In 2003, Kao was named a Chair Professor by speciaw appointment at de Ewectronics Institute of de Cowwege of Ewectricaw Engineering and Computer Science, Nationaw Taiwan University.[69] Kao den worked as de chairman and CEO of Transtech Services Ltd., a tewecommunication consuwtancy in Hong Kong. He was de founder, chairman and CEO of ITX Services Limited. From 2003 to January 30, 2009, Kao was an independent non-executive director and member of de audit committee of Next Media.[70][71]

Gugwiewmo Marconi, pioneer of wirewess tewecommunication, was awarded hawf of de 1909 Nobew Prize in Physics. In 2009, de century anniversary of Marconi's Nobew, Kao was awarded hawf of de same prize for his pioneer work on opticaw fibre which has "rewired de worwd". Kao was awso awarded de Marconi Prize in 1985, and is a Fewwow of de Marconi Society.

1989: The James C. McGroddy Prize for New Materiaws, American Physicaw Society (APS). Citation: "for contribution to de materiaws research and devewopment dat resuwted in practicaw wow woss opticaw fibers, one of de cornerstones of opticaw communications technowogy".[100]

1996: The Prince Phiwip Medaw of de Royaw Academy of Engineering, UK;[72] in recognition of "his pioneering work which wed to de invention of opticaw fibre and for his weadership in its engineering and commerciaw reawisation; and for his distinguished contribution to higher education in Hong Kong".

Kao's internationaw travews wed him to opine dat he bewonged to de worwd instead of any country.[134][135] An open wetter pubwished by Kao and his wife in 2010 water cwarified dat "Charwes studied in Hong Kong for his high schoowing, he has taught here, he was de Vice-Chancewwor of CUHK and retired here too. So he is a Hong Kong bewonger."[136]

On October 6, 2009, when Kao was awarded de Nobew Prize in Physics for his contributions to de study of de transmission of wight in opticaw fibres and for fibre communication,[138] he said, "I am absowutewy speechwess and never expected such an honour".[18][139] Kao's wife Gwen towd de press dat de prize wiww primariwy be used for Charwes's medicaw expenses,[140] after paying tax to de US government. In 2010 Charwes and Gwen Kao founded de Charwes K. Kao Foundation for Awzheimer's Disease to raise pubwic awareness about de disease and provide support for de patients.

In 2016, Kao wost de abiwity to maintain his bawance. At de end-stage of his dementia he was cared for by his wife and intended not to be kept awive wif wife support or have CPR performed on him.[142] Kao died at Bradbury Hospice in Hong Kong on 23 September 2018 at de age of 84.[143][144][145][146]

^a: Kao's major task was to investigate wight-woss properties in materiaws of optic fibers, and determine wheder dey couwd be removed or not. Hockham's was investigating wight-woss due to discontinuities and curvature of fibre.^b: Some sources show around 1964,[147][148] for exampwe, "By 1964, a criticaw and deoreticaw specification was identified by Dr. Charwes K. Kao for wong-range communication devices, de 10 or 20 dB of wight woss per kiwometer standard." from Cisco Press.[147]^c: In 1980, Kao was awarded de Gowd Medaw from American Armed Forces Communications and Ewectronics Association, "for contribution to de appwication of opticaw fiber technowogy to miwitary communications".[51]^d: In de United States Nationaw Academy of Engineering Membership Website, Kao's country is indicated as Peopwe's Repubwic of China.[82]^e:OFC/NFOEC – Opticaw Fiber Communication Conference and Exposition/Nationaw Fiber Optic Engineers Conference[127]

^"Draper Prize". draper.comg. Archived from de originaw on February 14, 2010. Retrieved November 4, 2009. "Charwes Kao is credited for first pubwicwy proposing de possibiwity of practicaw tewecommunications using fibers in de 1960s."

^1999 Charwes Stark Draper Award Presented "Kao, who was working at ITT's Standard Tewecommunications Laboratories in de 1960s, deorized about how to use wight for communication instead of buwky copper wire and was de first to pubwicwy propose de possibiwity of a practicaw appwication for fibre-optic tewecommunication, uh-hah-hah-hah."